Piston



March 9,19 3- D. BUSHBY ,313 320 PISTQN Filed June 14, 1940 2 Sheets-Sheet 1 March 9, 1943.

11 BUSHBY PISTON Filed Jime 14, 1940 2 Sheets-Sheet 2 I Patented Mar. 9, 1943 UNITED STATES PATENT OFFICE- PISTON David Bushby, Regina, Saskatchewan, Canada, assignor to The Vacuum Air Pressure Company Limited, Regina, Saskatchewan, Canada Application June 14, 1946, Serial No. 340,605

6 Claims.

My invention relates to improvements in pistons and an object of my invention is to provide a device of the character herewithin described which particularly when used in association with internal combustion engines andthe like, will constitute a highly eiiicient compression sealing means and thus greatly reduce the volume of unburnt gas which normally escapes past the pistons.

A further object of my invention is to provide adevice of the character herewithin described in which a combination heat dispersing means and a provision for uniform piston expansion is incorporated to eliminate the necessity of piston cam-grinding.

A further object of my invention i to provide a device of the character herewithin described in which an evenly expanding compression assembly is incorporated to assure uniform and circular wear 'of the cylinder wall. I

A further object of my invention is to provide a device of the character herewithin described wherein the compression assembly is normally held in an eiiiciently sealed contact with the cylinder wall, but may be easily and conveniently removed from the piston body for the purposes of replacement, inspection or renewal.

A further object of my invention is to provide a device of the character herewithin described which will eliminate the now commonly experienced conditon of piston or ring collapse.

A further object of my invention is to provide a device of the character herewithin described which is simple in structure, easy to assemble and such as will render a more eiiicient service for a greater length of time than has normally been obtainable with pistons employing-the conventional principles of design.

With the above more important objects in view and such other minor objects as may appear as the specification proceeds, my invention consists essentially in the arrangement and construction of parts all as hereinafter more particularly described, reference being had to the accompanying drawings, in which:

Figure 1 is a. side elevation of my evenly expanding piston, the same being partially broken away to reveal the structure of the compression assembly.

Figure 2 is a vertical cross-sectional elevation taken along the line 2-2 of Figure 1.

Figure 3 is a horizontal cross-sectional illustration taken along the line 3 3 of Figurel.

Figure 4 is a. further horizontal cross-sectional view taken along the line 4-4 of Figure 1.

set used in association with the piston shown in Figure 1.

In the drawings like characters of reference indicate corresponding parts in the difierent figures. l

The embodiment shown in the accompanying Figures 1 to 6 inclusive, comprising my uniformly expanding pistonassembly I will first be de-" scribed, the same consisting of a piston body 2 provided with a skirt 3 circumferentially tapered as at 4 outwardly from a transverse plane AA medially the length of the piston.

The lower edge 5 of the skirt is provided with a suitable reinforcing annulus 6 projecting in- 2 wardly therefrom and a vertically extending slot I is formed in the skirt between this edge and the plane AA thereof to facilitate free expansion.

A pair of annular, diametrically disposed piston pin bearings 9 are ecured only at the upper attaching portions III thereof to the piston body 2, the remaining downwardly depending portions of these, hearings being spaced A pair of suitable apertures l2 are provided in the bearings 9 to accommodate the conyen- I tional wrist pin I3 and a further pair of diametrically opposed apertures I4 are formed in the piston skirt 3 in longitudinal alignment with the apertures l2 to facilitate insertion of the pin I3 thereinto. A cotter key I5 passing transversely through each end of the pin serves to retain the pin in the desired position.

Two sets of three downwardly converging, inwardly projecting, heat dispersing ribs I6 are formed integrally with the piston body 2 and extend from the upper end of the latter to the attaching portions III of the bearings 9, the portions I! of the body being in turn, somewhat curved on the interior surface thereof and gradually '45 thickened as the ribs approach their junction with i the bearings.

Positioned upon the plane AA andadjacent the plane of the bearings 9, I provide a .pair of diametrically disposed, semicircular transverse slots I8 extending through the piston skirt 3 and amount of heat from the piston head I9 will be away therefrom, by the intervening chambers I I.

conducted and dissipated by the dispersing ribs l8 and the bearings 9. Consequently the portion of the body 2 located above the plane A-A will be subjected to a small degree of expansion which will take place within the usual clearance existing between the piston wall and the cylinder bore 2|, this expansion being uneven and most pronounced in the vicinity of the ribs where the mass of metal is greatest.

Since, however, the transverse slots l8 separate this expanding mass from the comparatively cooler portion of the piston body located under the plane A-A, the skirt 3 will not be distorted by the uneven expansion hereinabove described, but will expand uniformly around its entire circumference until the predetermined tapered clearance 4 is absorbed and the cylinder bore 2| contacted along the full length of the skirt. In this manner the conventional practice of piston cam grinding is of course, eliminated.

Positioned within the skirt 4 I provide an adjustable ring set 22 for preventing the collapsing thereof under progressive conditions of wear, the same being best illustrated in the accompanying Figures 2 and 6, and comprising a split ring 23 provided at the adjacent edges thereof with a pair or inwardly projecting ends 24 and 25. A pair of screw-threaded apertures 26 are formed in the former and the latter is equipped with a pair of drillings 21 aligned with but of a somewhat smaller diameter than the apertures 26. A pair of set screws 28 turned down at the ends 29 thereof are designed to extend into the drillings 21, the,

threaded portions 30 thereof being engageable with the apertures 26 and the annular shoulders 3| bearable against the end 25.

It will also be observed that the ends 24 and are of a somewhat restricted width at the portions 32 adjacent their attachment to the ring 23, and when the assembly 22 is being installed in position, the outer ofthe screws 28 should first be rotated to expand the rin and the adjacent skirt 4 to the desired extent. The inner screw then should be adjusted to the same degree of expansion, whereupon the original set-screw is removed and the resiliency imparted to the assembly thus formed by the portions 32 of the ends 24 and 25 utilized to urge the ring against the skirt 4.

Since many modifications can be made in the invention herein described and since the accompanying drawings have been prepared only to illustrate the relative arrangement and interaction of parts and not'with regard to accuracy of dimensions for manufacturing purposes which in view of this disclosure 1 consider to entail merely mechanical skill together with the skill of the mechanical draftsman, and since many apparently widely different embodiments of this invention may be made within the scope of the accompany ing claims without departing from the spirit and scope of the same, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense and I desire only such limitations placed thereon as justice dictates.

What I claim as my invention is:

1.' A piston body characterized by the provision of a skirt circumferentially tapering outwardly from a transverse plane medially of the length thereof, a pair of aligned, spaced diametrically disposed, annular, downwardly depending, piston pin bearings within the hollow interior of said skirt and spaced therefrom, said bearings being secured to said body at the upper parts only.

2. A piston body characterized by the provision of a skirt circumferentially tapering outwardly from a transverse plane medially of the length thereof, a pair of aligned, spaced diametrically disposed, annular, downwardly depending, piston pin bearings within the hollow interior of said skirt and spaced therefrom, downwardly converging, inwardly projecting, heat dispersing ribs extending between the upper end of said piston body and said bearings, said bearings being secured to said body at the upper parts only and to the lower ends of said ribs.

' 3. A piston body characterized by the provision of a skirt circumferentially taperin outwardly from a transverse plane medially of the length thereof, a pair of aligned, spaced diametrically disposed, annular, downwardly depending, piston pin bearings within the hollow interior of said skirt and spaced therefrom, being secured to said body at the upper parts only, said skirt being provided with a pair of diametrically disposed, transverse slots adjacent the plane of said bearings.

4. A piston body characterized by the provision of a skirt circumferentially tapering outwardly from a transverse plane medially of th length thereof, a pair of aligned, spaced diametrically disposed, annular, downwardly depending, piston pin bearings within the hollow interior of said skirt and spaced therefrom, downwardly converging, inwardly projecting, heat dispersing ribs extending between the upper end of said piston body and said bearings, said bearings being secured to said body at the upper parts only and to the lower ends of said ribs, said skirt being provided with a pair of diametrically disposed, transverse slots also positioned medially of the length of said piston skirt.

5. A piston body characterized by the provision of a pair of aligned, spaced, diametrically disposed, annular, downwardly depending piston pin bearings within the hollow interior of said piston body and spaced from the cylindrical side wall skirt thereof, said bearings beingsecured to said cylindrical side wall but at the upperparts only.

6. A piston body characterized by the provision of a pair of aligned, spaced, diametrically disposed, annular, downwardly depending piston pin bearings within the hollow interior of said piston and spaced from the cylindrical side wall thereof, and downwardly converging, inwardly projecting, heat dispersing ribs extending between the upper end of said piston body and said bearings, said bearings being secured to said cylindrical side wall but at the upper parts only.

DAVID BUSHBY. 

